Apparatus for prefabricating wooden panel frames

ABSTRACT

Apparatus for prefabricating wood frames for walls, ceilings and floors of buildings, mobile homes and sectional or stack housing, comprising a jig on which transverse and longitudinal members may be laid out in position for being nailed together, and a carriage carrying nailers movable along the jig in the direction of length of the longitudinal members for driving nails through the longitudinal members into the ends of the transverse members. The apparatus automatically senses the provision of multiple transverse member groups in a layout and provides automatically for movement of the carriage and operation of the nailers to nail not only the first but also the subsequent transverse members of such groups.

United States Patent [72] Inventor Walter George Moehlenpah Lldue. Mo.

(2| Appl. No. 1,395

[22] Filed Jana, I970 [45] Patented July 13. I971 [73] Assignee Hydro-Air Engineering, Inc.

St. Louis. Mo.

[54] APPARATUS FOR PREFABRICATING WOODEN I00, I01, 15!, 152, I53

[56] Relerences Clted UNITED STATES PATENTS Primary Examiner-Granville Y. Custer, Jr. Arromey- Koenig, Senniger, Powers 84 Leavitt ABSTRACT: Apparatus for prefabricating wood frames for walls, ceilings and floors of buildings, mobile homes and sectional or stack housing. comprising a jig on which transverse and longitudinal members may be laid out in position for being nailed together, and a carriage carrying nailers movable along the jig in the direction of length of the longitudinal members for driving nails through the longitudinal members into the ends of the transverse members. The apparatus automatically senses the provision of multiple transverse member groups in a layout and provides automatically for movement of the can riage and operation of the nailers to nail not only the first but also the subsequent transverse members of such groups.

PATENTEUJULIBIQH 3 59? 376 sum 3 or a FIG.4.

PATENIEB Jul! 3 IHII SHEEI l 0F 8 FIG.6

FIG. 5

FIG. 7

PATENTEI] JUL 1 319m FIG. 10

FIG. 9

FIG.12

FIG. 11

PATENIED JUL 1 3 Ian SHEEI 7 [If 8 APPARATUS FOR PREFABRICATING WOODEN PANEL FRAMES BACKGROUND OF THE INVEN'ITON The invention relates to apparatus of the class above described, for prefabricating wood frames for building walls for example, having a jig on which bottom and top plates of the frame (i.e., the longitudinal members) and studs (the transverse members) may be laid out in position for being nailed together and having a carriage carrying nailers movable along the jig for effecting nailing together of the bottom and top plates and the studs. It will be understood that many such wall frames have studs located at regular intervals (i.e., on 16 inch or 24 inch centers). However, adjacent openings for doors and windows it is desirable to have double studs (i.e., studs adjacent one another) and at the end of one of two wall sections whichjoin to form a corner ofa building it is desirable to have a pair of studs spaced apart the thickness of a stud to provide a corner nailing strip on each wall when the wall sections are assembled. Prior apparatus of the class above described is adapted to handle wall sections wherein the studs are located at regular intervals l6 inches or 24 inches centen to-center) but is not adapted to handle wall sections having multiple stud groupings, e.g., double studs, contiguous to one another or spaced apart the thickness of a stud. The carriage on such apparatus is driven by an electric motor with a brake actuated by limit switches which contact a stud and actuate the brake, stopping the carriage in position to nail the plates to the stud contacted. However, if the drive for the carriage IS rapid enough to efficiently traverse the 16 inches or 24 between studs, it cannot be started and stopped with the required accuracy to move the carriage the relatively short distances to a second stud when two studs are in contact or spaced apart the thickness of a stud.

SUMMARY OF THE INVENTION Among the several objects of the invention may be noted the provision of apparatus for efficiently and automatically nailing wood frame members together to form a frame, such as a frame for a wall, ceiling or floor of a building, mobile home or sectional or stack housing unit, wherein ransverse members are spaced at regular intervals (e.g., studs spac d 1 inches or 24 inches center-to-center) and which may be provided with double transverse members (cg, double studs) either contiguous to one another or spaced apart; and the provision of such apparatus which accurately automatically locates the double as well as single transverse members or studs.

In general such apparatus comprises a jig on which longitudinal and transverse wooden members may be laid out in position with the transverse frame members extending transverse- Iy between the longitudinal frame members at locations spaced longitudinally along the length of the longitudinal members for being fastened together to form a frame, a carriage movable longitudinally of the jig, fastening means carricd by the carriage for fastening the longitudinal members and transverse members together, a main drive for this carriage for driving it longitudinally along the jig from location to location and an auxiliary drive for the carriage for moving it forward along the jig through short distances from transverse member to transverse member at locations having more than one transverse member. Control of the drives and fastening means is provided by control means comprising means operable on forward movement of the carriage by the main drive to sense the arrival of the carriage at a position for the fastening means to operate to fasten a transverse member in place at any one of the locations and for thereupon deactivating said main drive to stop the carriage and then operating the fastening means. The control means further comprises means responsive to the presence or absence of a second transverse member at any one of the locations operable in conjunction with the sensing means for activating the main drive in response to the absence of a second transverse member and completion of operation of the fastening means at any location to drive the carriage forward to the next location, and for activating the auxiliary drive in response to the presence of a second transverse member and completion of operation of the fastening means at the first transverse member to drive the carriage forward to a position for the fastening means to fasten the second transverse member in place, and then operating the fastening means to fasten said second transverse member in place. Other objects and features will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan of apparatus of this invention, showing an arrangement of wood frame members on a jig and a carriage which traverses the jig and which carries nailers for automatically nailing the frame members together;

FIG. 2 is an elevation of the apparatus shown in FIG. 1;

FIG. 2A is a fragmentary side elevation;

FIG. 2B is a view showing certain mechanism for moving the nailers;

FIG. 3 is an enlarged partial section showing an indexing mechanism for advancing the carriage an incremental distance;

FIG. 4 is a plan of the indexing mechanism shown in FIG. 3;

FIGS. 5-l2 are enlarged partial sections illustrating the relationship of certain limit switches, which control the operation of the carriage and nailers, relative to certain studs as the limit switches cause the apparatus to perform various operations;

FIG. I3 is a hydraulic circuit diagram;

FIG. 14 is a pneumatic circuit diagram; and

FIG. 15 is an electrical circuit diagram.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, there is indicated at l a jig for the layout of longitudinal wood frame members 3 and 5 referred to as "plates" and studs 7 constituting transverse frame members in position for being nailed together to form a wooden frame F for a wall of a building. Typically, the plates 3 and 5 and stud 7 are two-by-fours, and are laid out with the plates 3 and 5 extending longitudinally of the jig at opposite sides of the latter, and studs 7 extending transversely of the jig between the plates, such that in the building the plates constitute bottom and top members with the studs extending vertically therebetween. The studs are positioned or laid out at lo cations such as indicated at A, B, C, D, E, F and G in FIG. 1, spaced at intervals along the length of the plates (and the jig). At certain locations, there are single studs (as shown at A, B, E and F in FIG. I) and at other locations there may be double studs 70 and 7!) adjacent each other as shown at C and D in FIG. 1. Or two studs 7c and 7d may be spaced apart the thickness ofa two-by-four by using spacers B as shown at G in FIG. 1. Pins for locating the studs are indicated at 9.

A carriage I1 is movable longitudinally of the frame, having wheels 13 which roll on tracks 15 at opposite sides of the frame. The carriage carries fastening means constituted by a pair of nailers, each designated 17, at opposite sides thereof for driving nails transversely through the plates 3 and 5 and endwise into the studs 7. Any type of commercially available automatic nail driver may be used; a Triad Spike Driver Model 640 manufactured by the Triad Manufacturing Corp. of Minneapolis, Minnesota, which drives two 16d (I6 penny) nails simultaneously has been used successfully. The carriage has a drive shaft indicated at 19 and a sprocket and chain drive 20 on each end thereof to drive pinions 21 in mesh with racks 23 extending lengthwise of the jig l at opposite sides thereof. The arrangement is such that when shaft 19 is driven in one direction the pinions and racks effect forward movement (right to left) of the carriage, and when shaft 19 is driven in the opposite direction the carriage is driven in reverse direction.

A main drive for the carriage for driving it longitudinally along the jig from location to location at relatively high speed is indicated generally at 25. This comprises a reversible hydraulic motor 27 mounted on the carriage 11. having its output shaft 29 connected as by means ofa chain and sprocket drive 30 to the drive shaft 19. A hydraulic pump 31 on the carriage supplies fluid under pressure to drive the hydraulic motor 27. The hydraulic pump 3! is a conventional variable displacement piston-type pump having a swash plate (not shown) the angle of which may be varied to change the flow of fluid delivered therefrom. A pneumatic cylinder 32 (see FIG. 14) is connected to the swash plate in such a manner that when the piston rod of the cylinder 32 is extended the pump 31 discharges fluid at a relatively high rate for operating the hydraulic motor 27 at a high speed to drive the carriage ll rapidly from location to location. and when the piston rod of the cylinder 32 is retracted the rate is reduced causing the hydraulic motor to slow down to decelerate the carriage so that it may be stopped within a controlled distance. The swash plate and pneumatic cylinder 32 thus constitute deceleration means for slowing down the carriage 11 in preparation for stopping it in position for the nailer 17 to drive nails into the studs.

Ari auxiliary drive for the carriage for moving it forward along the jig is indicated at 33. This auxiliary drive is an index ing drive, operable on each cycle of its operation. to index the carriage forward through a relatively small increment of distance (eg, the thickness of a two-by-four, generally about l% inches). More particularly, it comprises a conventional friction clutch 35 having a driving element 36 loose on shaft 19, a driven element 37 secured on shaft 19, and an air-actuated means 38 adapted when supplied with air under pressure to effect frictional engagement of the driving and driven ele ments. The driving element 36 is adapted to be oscillated by a drive comprising a pneumatic cylinder 39 having its piston rod 40 pin-connected at 4t to a triangular lever 42, and a link 43 interconnecting this lever and the driving element 36. The arrangement is such that on retraction of piston rod 40 with means 38 actuated to engage clutch elements 36 and 37. shaft 19 is rotated through an increment of are for driving the carriage 1] forward through an increment. Means 38 is deactu ated on extension of piston rod 40 so as not to rotate shaft 19 in reverse direction. Thus the auxiliary drive 33 will only drive the carriage ll forward, and it will not impede the rotation of the drive shaft 19 when the carriage is being driven by main drive 25. A movable stop indicated generally at 45 constitutes means for varying the are through which the drive shaft may be rotated by the auxiliary drive. and comprises a capscrew 47 and a locknut 49 and a block drilled and tapped for receiv ing the capscrew 47. The block and capscrew are disposed adjacent lever 42. Thus, by screwing and unscrewing the capscrew the are through which the lever 42 is rotated by the cylinder 39 as it strokes will be increased or decreased to vary the arc through which the shaft 19 rotates, thereby varying the incremental distance the carriage is advanced by the auxiliary or incremental drive.

Control means for the main and auxiliary drives and the nailers is indicated generally at 53 and comprises means 55 operable on forward movement of the carriage 11 by the main drive 25 to sense the arrival of the carriage at a position for the nailers to drive nails through the plates 3 and 5 and into a stud 7 in any one of the locations (A, B. C, D, E. F) and for thereupon deactivating the main drive to stop the carriage and then operating the nailers to drive the nails into the stud 7. The control means 53 also comprises means 57 responsive to the presence or absence of a second stud at any one of the loca tions (A. B. C. D. E, F and G) operable in conjunction with the sensing means 55 for activating the main drive 25 in response to the absence of a second stud and completion of operation of the nailers at any location to drive the carriage l1 rapidly forward to the next location. and for activating the auxiliary drive in response to the presence ofa second stud (as at location C, D or G) and completion of operation of the nailers at the first stud to drive the carriage ll forward to a position for the nailers to drive nails into the second stud and then operating the nailers to drive nails into the second stud.

The control means 53 is carried by the carriage I] and may comprise limit switches which are disposed to engage the studs or photocells and light sources or any other device which would detect the presence or absence of a stud and operate an electrical switch responsive to the presence of one or more studs at a location.

As illustrated in FlGS. 6]2. the means 57 of control 53 responsive to the presence or absence ofa stud comprises a limit switch [.51 and the sensing means 55 of control 53 comprises rearward limit switch LS2v The limit switches LS! and LS2 are of a conventional swing-arm type and have swing arms 59 and 61 extending down therefrom. At the free (lower) ends of the swing arms are rollers 63 and 65. The limit switches are mounted on a plate 67 fastened to the carriage. They are spaced apart longitudinally of the jig and disposed so that the rollers 63 and 65 engage the studs and close the switches as the carriage advances longitudinally along the jig. The rear limit switch LS2 is referred to as a trigger since it stops the carriage as it reaches a stud 7 and triggers the nailing operation when the carriage has come to rest in position to nail the plates 3 and 5 to the stud. The forward limit switch LS1 is referred to as a probe since it is adapted to sense the presence or absence of a second stud at a location and to cooperate with the trigger 55 to actuate the main drive 25 to rapidly advance the carriage 11 to the next location when the probe arm 6] is down in its unactuated position after completion of the nailing ofa single stud or a second stud and to actuate the auxiliary drive 33 to advance the carriage ll one or two incremental distances when the probe arm 6] is held up in its actuated position by a second stud after completion of the nailing of a first stud. The probe LS1 also actuates the deceleration means to slow down the carriage 11 in preparation for stopping it in position for the nailers to operate when the probe engages a stud 7 as the carriage ll is advanced by the main drive 25.

Control means 530 is disposed on the opposite side of carriage 11 and is identical to control means 53. The control means on one side of the carriage is selectively operable to prefabricate right-hand wall sections and the control means on the other side of the carriage is selectively operable to prefabricate left-hand wall sections. A switch 68 (FIG. 15) constitutes means for selectively activating one of the control means and deactivating the other and vice versa. The location of window and door openings in a wall section and the fact that the assembled wall section will be moved to other apparatus for subsequent operations (i.e., apparatus for applying sheathing) makes it desirable to sense the location of the studs from one side of the jig or the other (the top or bottom of the wall section). Short filler pieces as shown at H are often used above a door and. if sensed from the side of the wall section adjacent the top plate. they would stop the carriage adjacent the tiller piece in position to nail, which would undesirably cause nails to be driven through the bottom plate in the door opening. Whereas. if the control means adjacent the bottom is sensing the presence or absence of studs. the carriage would traverse a door opening and stop in position to nail the studs forming the opening. The switches of control means 530 are designated LS3 and LS4. LS3 being the probe and LS4 being the trigger.

Referring to FIG. 13, the hydraulic motor 27 of the main drive 25 for the carriage H is shown to be connected in a hydraulic circuit which includes the hydraulic pump 31 for delivering hydraulic fluid under pressure from a sump 69 to the motor under control of a valve H which constitutes a reversing and stop valve for the motor. This valve is a solenoid valve having two solenoids 73S and 755, the former being termed the forward solenoid since on energization thereof the motor is driven in the direction for forward movement of the carriage 11 and the latter being termed the reverse" solenoid since on energization thereof the motor is driven in the opposite direction for reverse movement of the carriage. Thus, on energization of the forward solenoid 73S, valve 7 I is set for delivery of pressure fluid via line 77 from the pump 31 to the valve 71 and line 79 from the valve 71, to the motor 27 and to return fluid to the sump 69 via lines 81 and 83. On energization of the reverse solenoid 755, the valve 71 is set for delivery of pressure fluid via line 77 from the pump 2I to the valve and via line 81 from the valve to the motor and to return fluid to the sump 69 via lines 79 and 83. When both solenoids are deenergized, the lines 79 and 8] are blocked at the valve 71 and the motor is stopped. A solenoid valve 85 is connected in a bypass line 87 across lines 79 and SI. This valve is normally closed and when it is energized it opens and bypasses fluid from the motor 27 to permit it to rotate when the auxiliary drive 33 is activated. The bypass constitutes means for allowing the drive shaft I9 to rotate without impedance from the main drive. Pressure controls are indicated at 88; gauges and throttle are indicated at 90; check valves are indicated at 9i; and a relief valve is indicated at 92.

Referring to FIG. 14, the pneumatic cylinder 39 of the auxiliary drive 33 is shown to be connected in a pneumatic circuit having an air supply line indicated at 93 with a surge tank 94 and an air reservoir 95. The pneumatic cylinder 39 is connected to line 93 a indicated at 97 under control ol'a solenoid valve 99. The arrangement is such that when solenoid valve 99 is deenergized, the piston rod 40 is extended; and when solenoid valve 99 is energized, the piston rod 40 is retracted to actuate the auxiliary drive 33. The air actuator 38 of the clutch 35 is connected to line 93 as indicated at I03 under the control of a solenoid valve I05. Solenoid valve I05 is adapted to supply air under pressure to line 103 when energized to operate the actuator 38 to engage clutch 35 and allow the au xiliary drive to advance the carriage. A pressure switch PSI connected to line I03 is adapted to form an interlock with the auxiliary drive 33 and with the bypass means 85, 87 for allow ing the drive shaft 19 to rotate without impedance from the main drive. This interlock keeps the carriage 11 under the control of either the main or auxiliary drive so that the carriage is either being driven or held stationary at all times.

At I09 in FIG. 14 are indicated pneumatic cylinders which operate certain clamps (not shown) for clamping the studs and plates (to be nailed) down against the jig so that the edges of the studs and plates will be in alignment when nailed. These cylinders are in a line [I0 connected to line 93 and are under the control of a solenoid valve III. The cylinders 109 are actuated to operate their respective clamps when the solenoid valve III is energized. A pressure switch PS2 connected to line 110 provides an interlock for the nailers and will not permit them to operate unless the clamps are pushing the studs and plates against the jig.

At 116 is indicated a pneumatic cylinder for moving the nailers inwardly via mechanism such as indicated at 1160 in FIG. 28 to clamp the plates to the studs before nailing them thereto, The cylinder II6 is connected to line 93 as indicated at 7 under the control of a solenoid valve I19 which when energized supplies air under pressure to the cylinder 116 to move the nailers inwardly and when deenergized supplies air under pressure to the cylinder 116 to move the nailers outwardly. A restriction 120 is provided at the discharge port of the valve 119 to slow down the action of the cylinder I16 as it approaches the ends of its stroke.

At l2l is indicated a cylinder for operating one nailer 17 and at I23 is indicated a cylinder for operating the other nailer I7. The cylinders 12] and I23 are under the control of the solenoid valves I25 and 127 respectively which actuate their respective nailers when they are energized and complete a cycle when deenergized. In a supply line 129 leading to each of the solenoid valves I25 and 127 are pressure regulators I31 and I33 which reduce the air pressure supplied to the nailers to 90 psi. A pressure switch PS3 connected to air reservoir 95 provides an interlock which will not permit the nailers to be actuated unless the pressure in the supply line I29 exceeds a predetermined value, such as 70 psi.

The pneumatic cylinder 32, adapted to vary the displacement of the hydraulic pump 3I as hereinbefore described, is shown to be connected in a line I36 under the control of a solenoid valve I37 which when energized operates the pneumatic cylinder 32 for high pump output and when deenergized operates cylinder 32 for low pump output.

Each of lines 97 and 136 includes means for regulating the speed at which the respective pneumatic cylinder is stroked in one direction, indicated generally at 14]. This comprises a check valve 143 and a throttling valve I45 piped in a circuit in parallel. The check valve allows unrestricted return flow of air from the cylinder and the throttling valve may be regulated to control the rate of airflow to the cylinder thereby controlling the speed at which the cylinder will operate. Line I36 also has such means for regulating the stroke in the other direction of cylinder 32.

Referring to FIG. I5, main power lines are indicated at L1 and L2, with fuses I46 and with an emergency stop switch I47 in L1. A coil 149 of a motor starter relay for the hydraulic pump 31 and two normally closed overload switches 150 are connected in a line 15I across lines LI and L2. Line 15I ineludes contacts a of a switch I53, and a line shunted around contacts a includes contacts I) of this switch. Line LI includes contacts c of switch I53 and a line 157 paralleling line LI includes contacts dof the switch. The switch has a contactor movable between an off position wherein all four contacts a, b, c and d are open, a manual position wherein contacts a and c are open and b and d are closed, and an automatic position wherein contacts a and c are closed and b and d open.

A relay CR1 has its coil connected across lines L1 and L2 via a line I59 including normally closed contacts CR6a of a relay CR6, two parallel lines I61 and I63, and a line I65. Line 161 includes the right-hand probe switch LS1 and contacts a of the switch 68. Line I63 includes the left-hand probe switch LS3 and contacts b of switch 68. A relay CR2 has its coil connected across lines L1 and L2 via line 159 including contacts CR6a, two parallel lines 169 and I71, and a line 173. Line 169 includes the right-hand trigger switch LS2 and contacts c of switch 68. Line I71 includes the left-hand trigger switch LS4 and contacts d of switch 68. The latter has a set of contactors movable alternately to close contacts b and d with contacts a and c open for operation on a left-hand wall section, and to close contacts a and c with contacts b and d open for operation on a right-hand wall section.

A relay CR3 has its coil connected across lines L1 and L2 via line 175. Line includes contacts CR4a of a relay CR4 and the pressure switch PSI. Connected to lines L2 and 175 in parallel with the coil of CR3 and the contacts of PSI via line I77 are normally closed contacts CR7a of a relay CR7 and a coil of solenoid I055 which operates the solenoid valve I05 controlling the clutch actuator 38.

A coil of solenoid 998 for actuating the solenoid valve 99 which controls the pneumatic cylinder 39 for the auxiliary drive 33 is connected across lines LI and L2 via line 179. Line 179 includes contacts CR4!) and CR3a of relays CR4 and CR3. Connected to lines L2 and 179 is parallel with the coil of solenoid 998 via line 181 is the coil of solenoid 855 which controls the bypass solenoid valve 85 for the main drive 25.

A relay CR5 has its coil connected across LI and L2 via line 183. Line I83 includes limit switch LS5 which is momentarily closed when the nailers move out, normally closed contacts CR4c, CRIb, CR6!) of relays CR4, CRI and CR6, and normally closed contacts a of a limit switch LS6 located on the carriage and adapted to slow down the carriage as it approaches either end of the track. Connected to lines L2 and I83 in parallel with the coil of relay CR5 and-the normally closed contacts CR4c, CRIb, LS6a and CR6!) via line 185 are the coil of relay-CR4 and contacts CR2a and CRIa of relays CR2 and CR1. Contacts CR3b of the relay CR3 are connected to line 185m parallel with the contacts CRIa vialine I87. A line I89 connects line 179 to line I85. Line I89 is connected to line 179 between the contacts CR4b and CR3a and to line 185 between the contacts CRZa and CRla. Contacts CRSa of the relay CR are connected to lines L1 and 183 in parallel with limit switch LS5 via line 190 and serve as hold-in contacts for the relay CR5 Connected to lines L1 and 183 in parallel with switch LS5 and contacts CR4c, CR1!) and LS6a via line 191 are normally closed contacts CR8a and CR4d of relays CR8 and CR4 and contacts a of a pushbutton switch PB2 which initiates the forward movement of the carriage and constitutes a forward start switch.

The coil of solenoid 1378 which actuates the solenoid valve 137 for shifting the hydraulic pump 31 to high flow is connected across lines L1 and L2 via line 193. Line 193 includes contacts CRSb of the relay CR5 and normally closed contacts CRa of a relay CR10. Connected to lines LI and 193 in parallel with the contacts CRSb via line 195 are contacts CR6c ofa relay CR6.

The coil ofa time-delay relay TD1 is connected across lincs L1 and L2 via line 197. Line 197 includes instantaneous contacts TDla of the time-delay relay TDl, normally closed contacts CR2b of relay CR2, and normally closed contacts LS7a of a limit switch LS7 which is adapted to stop the carriage as it approaches the forward end of the jig and to reverse its direction of travel for one second until the time-delay relay TDl has timed out after it is deenergized. Contacts CRSc of the relay CR5 are connected to lines L1 and 197 via line 199 in parallel with the contacts TDla and CRZb.

The coil of solenoid 738, which actuates the forward solc noid 735 of valve 71 which controls the supply of fluid to the hydraulic motor for driving the carriage forward, is connected across lines Ll and L2 via line 201. Line 201 includes contacts TDld which are closed instantaneously when the time-delay relay TD1 is energized The coil of solenoid 738 is also connected across lines L2 and 157 via line 203. Line 203 includes contacts b of the pushbutton switch P82. which serves as it jogging switch, and a manual switch for driving the carriage forward when the pushbutton P82 is depressed and switch 153 is in its manual position. Contacts PBZc of switch P132 in line 157 provide an interlock which prevents the nailer from being actuated when the carriage is being driven forward by depressing the pushbutton switch P82 and the switch 153 is set in its manual position.

The coil of relay CR6 is connected across lines L1 and L2 via line 205. Line 205 includes contacts I: of the limit switch LS7, normally closed contacts e of the time-delay relay TDI and normally closed contacts of a reverse stop limit switch LS8 which is adapted to stop the carriage when it returns to its starting position at one end of the jig Connected to line L1 is line 207 which includes contacts CR6d of the relay CR6. Line 207 may be connected to line 205 for tests; if so connected the contacts CR6d are connected in parallel with the b contacts of the forward stop limit switch LS7 to hold in the relay CR6 so that the carriage will run in reverse direction until it reaches a starting position at one end of the jig.

if it is desirable to have the carriage return to its starting position automatically when it reaches the forward end of the jig, means for raising the limit switches, which constitute the probes and triggers, should be provided so that these switches will not be actuated by engaging the studs as the carriage returns to its starting position.

A line 209 including contacts a of a pushbutton switch P83 connects lines 191 and 205 to connect the coil of relay CR6 to L1 and L2 through the contacts CR8a, CR4d, PB3a, TDle and LS8 so that when pushbutton P83 is held down the carriage will be driven in the reverse direction by the main drive. The various contacts in this circuit provide an interlock which prevents the carriage from being driven in the reverse direction when the nailers or auxiliary drive is being actuated.

A relay CRlO has its coil connected across lines L1 and L2 via line 211 which includes contacts b of the limit switch LS6 which is actuated when the carriage approaches either end of the jig to slow down the TD2 by deenergizing the solenoid 1375 which controls the hydraulic cylinder 32 which shifts the hydraulic pump 31 to low flow when deenergized.

The coil of solenoid 75$ for actuating the solenoid valve 71 to operate the hydraulic motor to drive the carriage in a reverse direction is connected across lines L1 and L2 via line 213 which includes contacts e of the relay CR6. Line 215 including contacts I) of the pushbutton switch P83 connects line 157 to line L2 through the coil of solenoid 75S and is adapted to energize the solenoid 755 to operate the main drive 25 in a reverse direction when the switch 153 is set on manual and the pushbutton PB3 is depressed. The 0 contacts of the pushbutton switch P83 in line 157 provide an interlock preventing the nailer from being operated manually when the carriage is being driven in the reverse direction by depressing the switch P83.

A relay CR7 has its coil connected across lines L1 and L2 via line 217. Line 217 includes contactsa ofa limit switch LS9 disposed to be closed when the pneumatic cylinder 39 of the auxiliary drive 33 retracts its piston rod 40 and normally closed contacts a ofa limit switch LSlO disposed to be opened when the pneumatic cylinder 39 of the auxiliary drive 33 has extended its piston rod 40.

A relay CR8 has its coil connected across lines L1 and L2 via line 219. Line 219 includes contacts CR7!) of the relay CR7 and normally closed contacts CR4e, TD2a and CRllJb of relays CR4, TD 2 and CR10. Line 221 connects lines 217 and 219. Line 221 is connected to line 217 between the contacts of LS9 and L810 and to line 219 between the contacts CR7b and CR4e. A line 223 includes instantaneous normally closed contacts TDlb and contacts TDlc of the timedelay TD1, the latter contacts being closed during the timing cycle which occurs when the relay TD] is deenergized. A line 225 includes the contacts CRSb of the relay CR8. The lines 223 and 225 are connected in parallel. Lines 223 and 225 are also connected to line Ll and to line 219 via line 226 in parallel with that portion ofline 219 which includes the contacts CR7!) and CR4e.

A line 227 is connected to L1 through contacts b ofa switch generally indicated at 229 and through the normally closed c contacts of a pushbutton switch P84. The b contacts of the switch 229 are closed when this switch is set in its run position.

The solenoid 1198 for energizing the solenoid valve 119 to actuate the cylinder 116 for moving the nailers inwardly has its coil connected across lines L2 and 227 via line 233 which includes contacts CRilc of relay CR8. Line 235 which includes contacts TD2c of a time-delay relay TD2 is connected to line 227 and line 233 so that the contacts TD2c and CRSc are connected in parallel.

A relay CR9 has its coil connected to lines L2 and 227 via line 237. Line 237 includes contacts b of the limit switch LS5 which close momentarily when the nailers move in, and normally closed contact TD2!) of the time-delay relay TD2.

A solenoid 1118 for actuating the solenoid valve 111 which operates the cylinders 109 which operate the clamps has its coil connected across the lines 227 and L2 via line 239 which includes contacts CR9a of the relay CR9. A line 24] connects lines 237 and 239. The line 241 is connected to line 237 between the contacts LSSb and TD2b and to line 239 between the contacts CR9a and the coil of solenoid 11151 The time-delay relay TD2 has its coil connected across lines L2 and 227 via line 243. Line 243 includes the pressure switch PS2 which is closed when the pressure in the air line to the cylinder for actuating the clamp reaches psi. and which is opened when the pressure reduces to 20 psi, the pressure switch PS3 which is closed when the pressure in the lines to solenoid valves and 127 is at 90 psi. and which is opened when the pressure drops below 70 psi and a limit switch LS1] which is closed when the nailers are pressing against the plates 3 and St A solenoid 1255 for actuating the solenoid valve 125 to cause one of the nailers to operate has a coil in a line 245 which is connected to lines L2 and 243 in parallel with the coil of the timedelay relay TD2. Line 245 includes contacts SW30 of an on-off switch SW3 for the one nailer. A solenoid 1275 for actuating the solenoid valve 127 to cause the other nailer to operate has its coil in line 247 which is connected to lines L2 and 243 in parallel with the coil of time delay relay TD2. Line 247 includes contacts SW4a of an onoff switch for the other nailer. Lines 245 and 247 are also connected in parallel with each other. Contacts TDZd of the timedelay relay TD2 are connected in parallel with the switch P830 and contacts LS1 In via line 249.

To provide for operating the nailers manually the switch in dicated at 153 is set on manual, the d contacts of switch 153 are closed to connect L1 to line 157, a contacts of the pushbutton switch PB4 and contacts of the switch indicated at 229 are closed to connect a line 251 to line 233. Thus when the pushbutton P84 is depressed the solenoid 1198 of solenoid valve 119 which controls the cylinder 116 to move the nailers inwardly is energized.

Line 157 is simultaneously connected to line 227 through In contacts of the pushbutton switch PB4 so that the nailers can be actuated though the same circuitry which operates them when the line 227 is connected to L2 through the c contacts of the switch 153v Contacts PB4c of the pushbutton switch PB4 open when the pushbutton is depressed to isolate the controls for the nailers from the controls for the carriage.

The operation of the above-described apparatus is as follows, assuming the wooden studs 7 and plates 3 and 5 are laid out on the jig l as shown in FIG. 1 in position for assembly and the carriage I] is in position ready to be moved forward over the frame members, the switch 153 is in its automatic position, the switch 229is set in the run position and switch 68 is set for a right wail section since the short filler piece at location H is on the left-hand side of the jig forming a right-hand wall section (if the filler piece were on the right-hand side of the jig, the switch SW2 would be set for a left-hand wall section). Thus, its contacts a and c are closed, and b and d are open, The pushbutton switch P82 is depressed energizing CR5, TD] and solenoid valve I37, the latter actuating cylinder 32 to cause the hydraulic pump 31 to shift into high flow, and also energizing solenoid 735 to actuate valve 71 to operate the hydraulic motor 27 and cause the main drive to move the carriage ll rapidly forward. The right-hand probe switch LS1 and trigger switch LS2 are in their deactivated position (see FIG. 5) as the carriage approaches the stud at location A. The roller 65 of the righthand probe switch LS1 engages the stud 7 and rolls over it (see FIG. 6) energizing CR1, deenergizing CR5 and solenoid valve 137 to thus cause the hydraulic pump 31 to be shifted to low flow to slow down the carriage 11. The roller 63 of the right-hand trigger switch LS2 engages the stud 7 (see FIG. 7) and the trigger switch LS2 is actuated to energize CR2, deenergizing TD1 and solenoid 738 to deactivate valve 71 and stop the hydraulic motor 27 by closing both intake and discharge ports of valve 71, thus stopping the carriage quickly. The trigger LS2 and nailers 17 are so disposed that the nailers are aligned with the center of the stud 7, in position for nailing as the carriage It stops. On deenergization of TD], CR8 is energized, energizing solenoid 1198 of valve 119 to actuate cylinder 116 to move the nailers l7 inwardly, When the nailers move in, they actuate switch LS5 to close its b contacts, energizing solenoid 111$ of valve 111 to cause the clamps for the studs and plates to clamp them against the jig, Pressure closes switch PS2 (PS3 is normally closed) and this results in energization of solenoids 1258 and 1278 to fire the nailers to drive nails through the plates and endwise into the stud 7. TD2 was energized when the nailers moved in and times out a delay interval (e.g., 4 seconds); relay CR9 is then deenergized to cause the clamp to move up. PS2 opens and the nailers move out. Since the probe switch [.51 is not activated (see FIG. 7) when the nailers 17 move out, the nailers actuate the limit switch LS5 which energizes the same circuit that was energized by the pushbutton P82 and causes the carriage 1-1- to be advanced rapidly to the next location by the main drive. This cycle is repeated as the carriage advances from location to location having a single stud.

When the carriage approaches a location with a second stud adjacent the first (i.e..locations C and D) the roller 65 of the right-hand probe switch LS1 engages the first stud 7a and rolls over it (see FIG, 8) which, as before, causes the hydraulic pump 27 to be shifted to low flow slowing down the carriage 11. The roller 63 of the nght-hand trigger switch LS2 engages the stud 7a to deenergize solenoid 735 the nailers activates the solenoid valve 71 to stop the hydraulic motor 27. As before, the nailers move inward, after which the clamps are actuated, the nailers are fired to drive nails into stud 7a and then the clamps and nailers are retracted. As shown in FIG. 8, the probe switch LS1 is so disposed with respect to the trigger switch LS2 that the roller 65 of the probe switch LS1 remains on top of the second stud 7b when the carriage stops to nail the first stud 7a to maintain switch LS1 activated. As thenailers move out, switch LS5 is closed and CR4 is energized. This results in energization of solenoid 1058 of valve 105 to effect engagement of the clutch 35. Pressure switch PS1 closes, energizing CR3, and thereby energizing solenoids 99S and S Solenoid 85S actuates bypass valve 85 for the main drive, freeing the drive shaft 19 from the main drive, and solenoid 99S actuates valve 99 to operate cylinder 39 of the auxiliary drive 33, thereby incrementally advancing the carriage 11 into position for nailing of the second stud 7b. As the piston rod 40 of cylinder 39 is retracted to effect a forward stroke of the carriage, switches LS9 and LS10 are closed. This results in energization of CR7, deenergizing solenoid 1058 of valve to disengage the clutch 35, and opening of pressure switch PS1 to deenergize CR3 to deenergize solenoids 99S and 858. As a result, cylinder 39 is actuated to extend piston rod 40 back to its initial position. When LS9 is closed, CR8 is energized and this operates the device, as before, through a nailing cycle to drive nails through the top and bottom plates 3 and 5 into stud 7b. As the nailers move out, they activate the limit switch LS5 to cause the carriage 1] to be driven rapidly to the next location. This cycle is repeated at locations having the double studs 7a and 719.

When the carriage approaches a location with the second stud 7d (see FIG. 10) spaced the thickness of a two-by-four away from the first stud 7c (i.e., location G) the roller 65 of the right-hand probe switch LS1 engages the first stud 7c and rolls over it which; as before, causes the hydraulic pump 27 to be shifted to low flow slowing down the carriage 11. The roller 63 of the right-hand trigger switch LS2 engages the stud 7c to deenergize solenoid 735, as before, which activates the solenoid valve 71 to stop the hydraulic motor 27 by shutting off both inlet and discharge ports to stop the carriage quickly. Then, as before, the nailers move inward, after which the clamps are actuated, the nailers are fired to drive nails into the stud 7d and then the clamps and nailers are retracted. As shown in FIG. 10, the probe switch LS1 is so disposed with respect to the trigger switch LS2 that the roller 65 ofthe probe is on top of the second stud 7d, thereby effecting incrementai advance of the carriage one step as before. As shown in FIG. 11, the roller 63 falls off stud 7c and the trigger switch LS2 is deactuated so that the nailers are not actuated; however, the probe switch LS1 is in its actuated position on stud 7d so as to cause the carriage to be advanced a second incremental distance by the auxiliary drive 33, moving the carriage to a position as shown in FIG, 12 with the trigger switch LS2 actuated by the stud 7 d and the probe switch LSl in its down or unactuated position allowing the trigger switch LS2 to actuate the clamps and nailers, as before, to drive nails through the plates 3 and 5 and endwise into the stud 7d. As the nailers move out limit switch [.35 is energized causing the carriage to be driven rapidly to the next location by the main drive.

As the carriage approaches the forward end of the jig, the limit switch LS6 is opened to deenergize CR5, thus deenergizing solenoid I37S of valve 137 to actuate cylinder 32 to reduce the flow ofhydraulic fluid from the pump to slow down the carriage, and prior to the carriage reaching the forward end of the jig, the limit switch LS7 is actuated to deenergize TD] which results in deenergization of the forward solenoid 375 to stop the hydraulic motor 31 and thus the carriage ll. The assembled frame F is then removed from the jig by a conveyor (not shown) which moves the assembled frame F to other apparatus for subsequent operation (ie, an apparatus for applying sheathing). Once the assembled frame F has been removed from the jig the reverse start pushbutton P83 is depressed and held down until the carriage returns to its start position at the other end of the jig. Depressing the reverse start pushbutton P83 energizes CR6 to cause the hydraulic pump 3] to deliver a high flow and the reverse solenoid 755 to be energized to cause the main drive 25 to drive the carriage rapidly back to its start position. As the carriage approaches the other end of the jig the slow down limit switch LS6 is actuated to cause the hydraulic pump 3] to deliver a lower flow of hydraulic fluid to slow down the main drive and thus the carriage. Before the carriage reaches the end of the jig the reverse stop switch LS8 is actuated to deenergize CR6 to deenergize the reverse solenoid 75S, shutting off the hydraulic lines to and from the hydraulic motor 27 to stop the carriage quickly With the carriage in its start position additional frame members are placed on the jig and the apparatus is ready to begin another cycle.

The carriage may also be advanced by the main drive 25 when the automatic manual switch 153 is set in manual position by depressing the forward start pushbutton switch P82; however the circuitry is such that the carriage will advance at its slow speed as long as the forward start switch is depressed. The carriage may also be driven at slow speed in its reverse direction by depressing and holding down the reverse pushbutton F33. The nailers may be actuated when the switch 153 is set on manual; however they are interlocked with the forward and reverse pushbuttons P82 and PBS so that the nailers cannot be actuated when the carriage is being moved in either direction.

By utilizing three limit switches or other suitable means to sense the absence or presence of a second stud at a location, apparatus having similar circuitry may be adapted to sense a single stud at a location and after nailing it in place to actuate the carriage to drive it rapidly to the next location; to sense a second stud adjacent the first stud and after nailing the first stud in place to advance the carriage an incremental distance positioning the carriage for nailing the second stud in place and then after nailing the second stud in place advancing the carriage rapidly to the next location; and to sense a second stud spaced the thickness of a two-by-four away from the first stud and to advance the carriage two incremental distances after the first stud has been nailed positioning the carriage for nailing the second stud in place and then after nailing the second stud advancing the carriage rapidly to the next loca tion. if desired, a switch may be provided to adapt such apparatus to selectively nail or not nail the second stud when two studs are adjacent each other as normally the two adjacent studs such as 7a and 7b are nailed together before they are placed in the jig and nailing one ofthe studs may be sufficient.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above construction: without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrstive and not in a limiting sense.

What I claim is:

1. Apparatus for prefabricating wood frames having transverse frame members extending transversely between longitudinal frame members at locations spaced longitudinally along the length of said longitudinal members, and which may have one or more transverse members at each location, said apparatus comprising a jig on which longitudinal and transverse members may be laid out in position for being nailed together to form a frame, a carriage movable longitudinally of the jig, fastening means carried by the carriage for fastening the iongitudinal members and transverse members together, a main drive for the carriage for driving it longitudinally along the jig from location to location, an auxiliary drive for the carriage for moving it forward along the jig through short distances from transverse member to transverse member at locations having more than one transverse member, and control means for said drives and said fastening means comprising means operable on forward movement of the carriage by said main drive to sense the arrival of the carriage at a position for the fastening means to operate to fasten a transverse member in place at any one of said locations and for thereupon deactivating said main drive to stop the carriage and then operating the fastening means, and means responsive to the presence or absence of a second transverse member at any one of said locations operable in conjunction with said sensing means for activating said main drive in response to absence of a second transverse member and completion of operation of the fasten ing means at any location to drive said carriage forward to the next location, and for activating said auxiliary drive in response to the presence of a second transverse member at any location and completion of operation of the fastening means at the first transverse member at said location to drive said carriage forward to a position for the fastening means to fasten the second transverse member in place, and then operating the fastening means to fasten said second transverse member in place.

2. Apparatus as set forth in claim 1 wherein the fastening means comprises nailers positioned to drive nails transversely through the longitudinal members and endwise into the trans verse members.

3. Apparatus as set forth in claim i wherein said auxiliary drive is a cyclic indexing drive operable on a cycle thereof to advance the carriage through an incremental distance.

4. Apparatus as set forth in claim I having a rotatable drive shaft for driving the carriage and wherein said auxiliary drive comprises a clutch having a driving element loose with respect to the drive shaft and a driven element secured to the drive shaft, power means on the carriage for oscillating said driving element, and means for effecting engagement of said clutch elements on movement of said driving element in the direction of rotation of the drive shaft in the direction to move the carriage forward.

5. Apparatus as set forth in claim 1 having a drive shaft for the carriage and wherein the main drive includes a motor, means for connecting said motor to said drive shaft for driving the carriage, and means for freeing said drive shaft to rotate without impedance from the main drive while the carriage is being driven by the incremental drive.

6 Apparatus as set forth in claim 4 wherein the auxiliary drive comprises means for varying the are through which said drive shaft may be rotated by said auxiliary drive thereby varying the incremental distance the carriage is advanced by said auxiliary drive.

7. Apparatus as set forth in claim 1 wherein said control means comprises at least two limit switches, a forward limit switch and a rearward limit switch, said limit switches being mounted on the carriage, spaced apart longitudinally of the jig and disposed to engage the transverse members as the carriage advances longitudinally along the jig, the rearward limit switch constituting said means operable on forward movement of the carriage by said main drive means to sense the arrival of the carriage at a position for the fastening means to fasten a trans verse member at any one of said locations and then operating the fastening means to fasten said transverse member in place and the forward limit switch constituting means responsive to the presence or absence of a second transverse member at any one of said locations operable in conjunction with said sensing means for activating said main drive in response to absence of a second transverse member and completion of operation of the fastening means at any location to drive said carriage rapidly forward to the next location and for activating said auxiliary drive in response to the presence of a second transverse member at any location and completion of operation of the fastening means at the first transverse member at said location to drive said carriage forward to a position for the fastening means to fasten the second transverse member in place and then operating the fastening means to fasten said second transverse member in place.

8. Apparatus as set forth in claim 1 having fastening means at opposite sides of the carriage and wherein control means for said drives and said fastening means is disposed on each side oi the carriage. the control means on one side of the carrisge being selectively operable to prsfsbrlcste right-hand frames and the control means on the other side of the carriage being selectively operable to prefsbrieate left-hand frames and means for activating one of said control means and deactivating the other and vice versa.

9. Apparatus as set forth in claim 2 wherein said control means comprises at least two limit switches on each side of said carriage, for making frames for rightand left-hand wall sections, the limit switches on one side forming a set of limit switches adapted for prefabricating right-hand wall sections and the limit switches on the other side forming another set of limit switches adapted for prefabricating left-hand wall sections, and means for selectively activating either set of said limit switches for controlling the main and auxiliary drives and the nailers to automatically nail the frame members together to prefabricate rightor left-hand wall sections.

10. Apparatus as set forth in claim 1 wherein the main drive is operable at relatively high speed for advancing the carriage rapidly from location to location and deceleration means is provided for slowing down the carriage in preparation for stopping it in position for the fastening means to fasten the transverse members in place.

ll. Apparatus as set forth in claim wherein the deceleration means is activated by means responsive to the presence or absence of a second transverse member in response to the presence of a transverse member at any location, and the deceleration means is deactivated in response to the completion of the fastening operation at any location.

12. Apparatus for prefabricating wood frames having transverse frame members extending transversely between longitu dinal frame members at locations spaced longitudinally along the length of said longitudinal members. and which may have one or more transverse members at each location. said spparatus comprising a jig on which longitudinal and transverse members may be laid out in position for being nailed together to form a frame, a carriage movable longitudinally of the jig, fastening means carried by the carriage for fastening the iongitudinal members and transverse members together, drive means for the carriage for driving it longitudinally along the jig, and control means for said drive means and said fastening means comprising means responsive to presence of a transverse member operable on forward movement of the carriage by said drive means to sense the arrival of the carriage at a position for the fastening means to operate to fasten said transverse member in place, and for thereupon deactivating said drive means to stop the carriage and then operating the fastening means. and means responsive to the presence or absence of a second transverse member at any one of said locations operable in conjunction with said sensing means for activating said drive means in response to absence of a second transverse member and completion of operation of the fastening means at any location to drive said carriage forward to the next location, and for activating said drive means in response to the presence of a second transverse member at any location and completion of operation of the fastening means at the first transverse member at said location to drive said carriage forward to a position for the fastening means to fasten the second transverse member in place, and then operating the fastening means to fasten said second transverse member in place. 

1. Apparatus for prefabricating wood frames having transverse frame members extending transversely between longitudinal frame members at locations spaced longitudinally along the length of said longitudinal members, and which may have one or more transverse members at each location, said apparatus comprising a jig on which longitudinal and transverse members may be laid out in position for being nailed together to form a frame, a carriage movable longitudinally of the jig, fastening means carried by the carriage for fastening the longitudinal members and transverse members together, a main drive for the carriage for driving it longitudinally along the jig from location to location, an auxiliary drive for the carriage for moving it forward along the jig through short distances from transverse member to transverse member at locations having more than one transverse member, and control means for said drives and said fastening means comprising means operable on forward movement of the carriage by said main drive to sense the arrival of the carriage at a position for the fastening means to operate to fasten a transverse member in place at any one of said locations and for thereupon deactivating said main drive to stop the carriage and then operating the fastening means, and means responsive to the presence or absence of a second transverse member at any one of said locations operable in conjunction with said sensing means for activating said main drive in response to absence of a second transverse member and completion of operation of the fastening means at any location to drive said carriage forward to the next location, and for activating said auxiliary drive in response to the presence of a second transverse member at any location and completion of operation of the fastening means at the first transverse member at said location to drive said carriage forward to a position for the fastening means to fasten the second transverse member in place, and then operating the fastening means to fasten said second transverse member in place.
 2. Apparatus as set forth in claim 1 wherein the fastening means comprises nailers positioned to drive nails transversely through the longitudinal members and endwise into the transverse members.
 3. Apparatus as set forth in claim 1 wherein said auxiliary drive is a cyclic indexing drive operable on a cycle thereof to advance the carriage through an incremental distance.
 4. Apparatus as set forth in claim l having a rotatable drive shaft for driving the carriage and wherein said auxiliary drive comprises a clutch having a driving element loose with respect to the drive shaft and a driven element secured to the drive shaft, power means on the carriage for oscillating said driving element, and means fOr effecting engagement of said clutch elements on movement of said driving element in the direction of rotation of the drive shaft in the direction to move the carriage forward.
 5. Apparatus as set forth in claim 1 having a drive shaft for the carriage and wherein the main drive includes a motor, means for connecting said motor to said drive shaft for driving the carriage, and means for freeing said drive shaft to rotate without impedance from the main drive while the carriage is being driven by the incremental drive.
 6. Apparatus as set forth in claim 4 wherein the auxiliary drive comprises means for varying the arc through which said drive shaft may be rotated by said auxiliary drive thereby varying the incremental distance the carriage is advanced by said auxiliary drive.
 7. Apparatus as set forth in claim 1 wherein said control means comprises at least two limit switches, a forward limit switch and a rearward limit switch, said limit switches being mounted on the carriage, spaced apart longitudinally of the jig and disposed to engage the transverse members as the carriage advances longitudinally along the jig, the rearward limit switch constituting said means operable on forward movement of the carriage by said main drive means to sense the arrival of the carriage at a position for the fastening means to fasten a transverse member at any one of said locations and then operating the fastening means to fasten said transverse member in place and the forward limit switch constituting means responsive to the presence or absence of a second transverse member at any one of said locations operable in conjunction with said sensing means for activating said main drive in response to absence of a second transverse member and completion of operation of the fastening means at any location to drive said carriage rapidly forward to the next location and for activating said auxiliary drive in response to the presence of a second transverse member at any location and completion of operation of the fastening means at the first transverse member at said location to drive said carriage forward to a position for the fastening means to fasten the second transverse member in place and then operating the fastening means to fasten said second transverse member in place.
 8. Apparatus as set forth in claim 1 having fastening means at opposite sides of the carriage and wherein control means for said drives and said fastening means is disposed on each side of the carriage, the control means on one side of the carriage being selectively operable to prefabricate right-hand frames and the control means on the other side of the carriage being selectively operable to prefabricate left-hand frames and means for activating one of said control means and deactivating the other and vice versa.
 9. Apparatus as set forth in claim 2 wherein said control means comprises at least two limit switches on each side of said carriage, for making frames for right- and left-hand wall sections, the limit switches on one side forming a set of limit switches adapted for prefabricating right-hand wall sections and the limit switches on the other side forming another set of limit switches adapted for prefabricating left-hand wall sections, and means for selectively activating either set of said limit switches for controlling the main and auxiliary drives and the nailers to automatically nail the frame members together to prefabricate right- or left-hand wall sections.
 10. Apparatus as set forth in claim 1 wherein the main drive is operable at relatively high speed for advancing the carriage rapidly from location to location and deceleration means is provided for slowing down the carriage in preparation for stopping it in position for the fastening means to fasten the transverse members in place.
 11. Apparatus as set forth in claim 10 wherein the deceleration means is activated by means responsive to the presence or absence of a second transverse member in response to the presence of a transverse member at any location, and the deceleration means is deactivated in response to the completion of the fastening operation at any location.
 12. Apparatus for prefabricating wood frames having transverse frame members extending transversely between longitudinal frame members at locations spaced longitudinally along the length of said longitudinal members, and which may have one or more transverse members at each location, said apparatus comprising a jig on which longitudinal and transverse members may be laid out in position for being nailed together to form a frame, a carriage movable longitudinally of the jig, fastening means carried by the carriage for fastening the longitudinal members and transverse members together, drive means for the carriage for driving it longitudinally along the jig, and control means for said drive means and said fastening means comprising means responsive to presence of a transverse member operable on forward movement of the carriage by said drive means to sense the arrival of the carriage at a position for the fastening means to operate to fasten said transverse member in place, and for thereupon deactivating said drive means to stop the carriage and then operating the fastening means, and means responsive to the presence or absence of a second transverse member at any one of said locations operable in conjunction with said sensing means for activating said drive means in response to absence of a second transverse member and completion of operation of the fastening means at any location to drive said carriage forward to the next location, and for activating said drive means in response to the presence of a second transverse member at any location and completion of operation of the fastening means at the first transverse member at said location to drive said carriage forward to a position for the fastening means to fasten the second transverse member in place, and then operating the fastening means to fasten said second transverse member in place. 